Many consumer electronics today include optical finger navigation (OFN) modules for a user to input through a GUI (Graphical User Interface). Many of these products also include an ambient light sensor module for sensing the ambient light. The ambient light intensity level detected by the ambient light sensor module is used to facilitate various functions such as the automatic adjustment of the screen brightness. However, as the optical finger navigation module and the ambient light sensor module are typically discrete components in such a product, the total component count of the product is relatively large. Because of this, the size and the weight of the product are also relatively large, and the cost of the product is relatively high.